The present invention generally relates to a process for encasing articles and, in particular, relates to one such process wherein a tension medium is cooled to a sub-ambient temperature.
Cold-shrinking products for encasing articles are most frequently used whenever heat or open flames are undesirable. One particular application for such cold-shrinking products is in the encasement of cable splices and cable termination.
In general, cold-shrinking products are known, for example, from U.S. Pat. No. 3,515,798. Therein, a product is discussed wherein a wire helix is placed inside a radially expanded hose made of a rubbery elastic material to maintain the hose in the expanded condition. Upon removal of the wire helix the radially expanded hose shrinks onto the article to be encased.
A hose made of a cross-linked elastomer insulation material is discussed and described in DE-OS 26 47 122. Therein the hose is kept in the expanded condition by a tension medium applied to the outer surface of the hose. The tension medium is bonded to the surface of the expanded hose, but can be loosened or removed from the hose surface for the purpose of shrinking. In order to remove the tension medium, the bond between the hose and the tension medium can be removed, e.g. by use of a solvent that dissolves the bonded connection. However, the use of many such solvents during such an installation procedure is, in most cases, excluded because of environmental considerations.
Alternatively, the tension medium can be removed from the surface of the expanded hose by, for example, shattering or by peeling it off in strips. In the latter case, a layer of a thermoplastic material is extruded over the hose in the form of a tube-like sheath, the sheath is formed of a hard plastic selected for the purpose of shattering, or has predetermined helical breaking points located in the surface thereof for the purpose of peeling.
The use of tension media made of hard brittle plastic severely limits the application thereof because very often the article to be encased is not flexible. Furthermore, there is the additional inherent danger of the involuntary destruction of the tension medium, e.g. due to an accidental impact. Such an involuntary destruction renders the article unusable.
The subsequent incorporation of the predetermined breaking points is an additional work step making the article more expensive. Further, in both cases, the article must be processed, after it has been placed in the shrinking position, which requires the use of both hands by the installer, in each case.
Consequently, it is highly desirable to provide a process for encasing an article that obviates the above-identified difficulties associated with conventional processes and which is cost effective